Hidden diversity in Arctic kelp beds

Kelps (brown seaweeds of the order Laminariales) form dense underwater forests along rocky coastlines of Arctic and temperate regions, providing habitat and shelter to a vast number of associated organisms. Until recently the common opinion was that we have four European Arctic kelp species in total. DNA fingerprinting tools however revealed that one species, hitherto assigned to Laminaria digitata, actually forms a morpho-species complex comprising two morphologically very similar species from two genera (Laminaria digitata and Saccharina groenlandica). Most probably only the hitherto hidden species S. groenlandica which is more cold-adapted than L. digitata is biomass dominant in the Arctic around the Svalbard archipelago. Both species are not readily distinguishable by external morphology, but one anatomical marker has been suggested to serve as species marker. This is the presence of slime channels (mucilage ducts) in blades, stipes or both which are visible in cross sections. As we identified a considerable biomass change in kelp species, especially in the ‘Laminaria digitata’ species complex, in Kongsfjorden, western Svalbard between 1996/98 and 2012/2013 due to climate change, it is urgently needed to verify the actual species identity of these kelps. Thus the master student shall focus on the investigation of this aspect during our summer expedition 2015 to Kongsfjorden.

The task will be to quantitatively assign the species identity hitherto attributed to ‘Laminaria digitata’ to either L. digitata or Saccharina groenlandica by a combined approach using morpho-anatomical characters and DNA fingerprinting tools. In order to do so, kelp specimens will be quantitatively collected along a sub-littoral depth transect between 0 and 10 m in Kongsfjorden.

Objectives and Tasks
The following research questions shall be answered:
• Do kelp species with a divided lamina growing off Hansneset, Blomstrand, Kongsfjorden, belong to one or two kelp species and if yes in which proportions?
• Can the ‘mucilage duct’ criterion be verified and are there any other morphological criteria which enable the discrimination of these two species?
• Which sporophyte size / age are needed to develop mucilage ducts?

Weitere Informationen

Unternehmen

Helmholtz Gemeinschaft

Bereich/Abteilung

Alfred-Wegener Institute, Helmholtz Centre for Polar and Marine Research

Abschlussart

Bachelorarbeit

Branche

Bio- und Gentechnologie

Anforderungen

• basic knowledge about molecular techniques and marine biology/seaweeds desirable;
• there is the possibility to accompany a field course in March 2015 to Helgoland (North Sea);
• a scientific diver’s licence would be very welcome;

Zusatzinformationen

For spring / summer 2015 we are looking for a Master student (Biology / Botany / Marine Biology)

Time and Location:

Practical field work will take place at the Koldewey station, Ny Alesund, Spitzbergen between June and July 2015. Preparatory work (training in DNA extraction and amplification and anatomical work) will take place in Bremerhaven between April and May 2015 (dates to be agreed upon); data evaluation after the expedition in the home laboratory, travel expenses will be paid by the Alfred Wegener Institute

contact:

Dr. Inka Bartsch, Inka.Bartsch(at)awi.de, 0471 / 4831-1404
Dr. Sandra Heinrich, Sandra.Heinrich(at)awi.de